Steam-boiler economizer and method of operating the same.



STEAM BOILER ECONOMIZ APPLICATION FILED DEC. 8.19M.

D. S. JAC'OBUS.

ER AND METHOD OF OPERATING THE SAME.

Patented Tlieb. 5, 191&

3 SHEETSSHEET I.

' ATTORNEY D. s. JACOBUS.

STEAM BOILER ECONOMIZER AND METHOD OF OPERATING THE SAME.

APPLICATION FILED DEC. 8. 1914.

3 SHEETS-SHEET 2- INVENTOI? BY A 9/ M ATTORNEY/ 0. s. mcosus. STEAMB'OILER ECONOMIZER AND METHOD OF OPERATING THE SAME.

APPLIQATION FILED DEC.8, I914;

Patented Feb '3 SHEETSSHEET a 'IIVI/EIVTOR 19M 11). BY I I T BAA/Y1)WATTORA/EVM WITNESSES.- Q I p 1 DAVID S. JACOBUS, OE JERSEY CITY, NEWJERSEY, ASSIGI NOEI T0 THE EABCOCK & WIJLCOX COMPANY, OF JBAYONN E, NEWJERSEY, A CORRORATION OF NEW JERSEY.

STEAM-BOILER ECONOMIZER AND METHOD OF OPERATING THE SAME.

To all whom it may concern:

Be it known that I, DAVID S. JACOBUS, a citizen of the United States,residing in J ersey City, in the county of Hudson and State of NewJersey, have invented certain new and useful Improvements inSteam-Boiler Economizers and Methods of Operating the Same, of which thefollowing is a specification.

Corrosion or pitting in the interior of a boiler is due to elements inthe water that oxidize or otherwise afiect the iron. Ihis is oftenprevented or minimized by the addition to the water of a neutralizingreagent,

such as carbonate of soda or lime, the re-- agent being added until itaccumulates in the boiler t a point where the amount per gallon of waterin the boiler, or the degree of concentration, is such as to efiect thedesired result. After the reagent is added it remains in the boiler asit is not evaporated in producing steam and the amount of the reagentthat must be supplied after the first reagent is added will be only thatrequired to make up for any chemical action, or for the amount that islost in blowing down the boiler. The reagent may be added at intervalsto the boiler, say once per day, or it may be added continuously to thefeed water. If added continuously to the feed water the amount pergallon of feed water may be less 'than that needed to prevent thecorrosion,

and the' 'reagent may be allowed to concentrate-in the boiler to theproper point; for example, the feed water might be treated with twograins of the reagent per gallon which could be allowed to concentratein the boiler to twenty grains per gallon, and the twenty grains pergallon might give good results where the two grains per gallon wouldnot.

An economizer cannot be protected from interior corrosion by theaddition of a reagent from time to time as in a boiler as the reagent'would pass directly through the economizer with the water, again,should the reagent be added continuously to the feed water, it cannot bemade to concentrate in the economizer in the way that it does in aboiler. In the numerical example just given, if twenty grains wereneeded to prevent corrosion, it would be necessary to treat the feedwater with twenty grains of the reagent per gallon to properly protectthe economizer, which would make the treatment Specification of LettersPatent.

,and carbo ic acid gas in the feed water add to, or in some cases may hethe sole cause of, corrosion.

Patented F sh. 5, I911, Application filed December 8, 1914. Serial No.876,013.

The tendency in modern power plant practice is toward large size boilerunits and high overloads, and to maintain a high capacity the boilermust be kept clean on its interior, otherwise there will be tubedifliculties. It is, therefore, of extreme importance that the boilerfeed water shall be of a high degree of purity and to meet the presenttendency the practice is to cut down the amount 'of make-up water, toavoid the formation of scale in the tubes, and to in crease the amountfrom the hot well, the latter being distilled water coming fromthecondensers in the plant. But water of p the desired purity for theboiler will cause trouble through corrosion of the economizer,particularly if it is one of wrought iron or wrought steel.

The purpose of the present invention is toaid in preventing internal andexternal corrosion of a two-stage economizer which may be such asdescribed in my Patent No. 1,219,320 granted March 13, 1917. In such twostage economizers the water passing to the high pressure stage is heatedsolely by the waste gases. In my present invention I use some of theboiler water to aid in heating the water passing into the high pressurestage, and also introduce elements which aid in preventing corrosion ofthe tubes of the high pressure stage.

My invention will be understood by ref erence to the accompanyingdrawings in which Figure 1 is a somewhat diagrammatic side elevation,partly in section, of a plant comprising a two-stage economizer; Fig. 2a diagrammatic plan to illustrate the use of my invention in connectionwith a plurality of boilers; and Fig. 3 a diagrammatic plan View of twoboiler units, each having its individual mingling tank. Similarreference numerals indicate similar parts in the several views.

In Fig. 1 I have shown a boiler-of standard design in which the numeral.1 designnates a bank of inclined generating tubes expanded into frontand rear headers. The boiler may be fired by any well-known or usualmeans, a chain grate stoker 2 being indicated. The-gases from thefurnace flow through the boiler, as indicated by the arrows, to a flue 3leading to the uptake 4. Located inthe flue and, as shown, above theboiler, is an economizer comprising a low pressure stage 5 and a highpressure stage 6. These stages consist of tubes fitted into upper andlower boxes, the high pressure stage, composed of wrought iron orwrought steel tubes and headers and subjected to the action of the.hottest gases, and the low pressure stage composed of cast iron tubesand headers and subjected to the action of the coldest gases. [7indicates the source of the main supply, such as the hot well, to whichthe condensed steam from the plant is run, this being distilled waterand practically free of chemical reagents. The main supply of water ispumped by a pump 8 through pipe 9 to the low pressure stage 5. The waterflows through the tubes of the low pressure stage and leaves said stagethrough pipe 10, and is delivered into a tank 11 near the upper partthereof. .A valved pipe 12 leads from the boiler, from the steam andwater drum 13, through the connection 13, or from the mud drum 13through the connection 13 through which pipe 12 boiler water is forcedinto tank 11 where it is caused to'mingle with the main supply byflowing over a' series of perforated shelves 14f A relief valve 15 isplaced above the tank 11, and the air and gases permitted to escapethrough said valve, or are withdrawn through a separate connection 16 towhich an 61601301 or air pump may be connected to maintain the pressurebelow that of the atmosphere, if desired. The tankll is provided with ablow-off connection 11 for removing any mud or sediment that may bedeposited.

The tank 11 serves the purpose of mingling the water from the lowpressure stage of the economizer with a certain amount of water from theboiler and of permitting air and gases to escape from the water after ithas been heated, corrosion of the high pressure stage by air or gasesbeing thereby prevented or minimized by the'removal of the air or gases,and through the introduction of certain elements in the boiler water.The

- water from tank 11 flows downward through pipe 17 to pump 18, and isforced by the latter through pipe 19, against the boiler pressure, tothe inlet end of the high pressuredensity of the water.

'11 can be made to contain a sufficient amount of the reagent to preventinterior corrosion of the tubes of the high pressure stage withoutraising the temperature of the water in the tank above a point whichwill interfere with the economy of the plant. The amount of the chemicalreagent in solution in the boiler may be graduatedby adding more or lessof such reagent, either intermittently or continuously, to the tank 11or by introducing it into the hot well. The degree of concentration ofthe Water in the boiler may be determined by the standard method ofchemical titration, v or by measuring the The make-up Water may beintroduced into the hot well 7 or the tank 11, and if a chemicaltreatment is necessary the reagent may be introduced along with themake-up water. i

The water from the hot well 7, which enters the low pressure stage ofthe economizer through pipe 9, may be at the temperature ofapproximately F., and this water is heated when it passes through thelow pressure economizer stage. When mingled with the boiler water thetemperature of the water in tank 11 is above a temperature which willprevent sweating on the outside of the wrought iron or steel tubes ofthe high pressure stage 6, say 120 F., and this prevents corrosion onthe exterior of said tubes. As

the pressure in stage 5 of the economizer isv From the foregoingdescription it will be seen that I prevent or minimize corrosion of thehigh pressure stage of the economizer, by eliminating the air and gasesfrom the water, and by adding a certain amount of water from the boilercontaining elements which resist corrosion.

The description and drawings give what I consider the preferable way ofapplying the invention to a two stage economizer, namely, by introducingthe water from the boiler into the inlet to the high pressure stage. Incertain instances it may be advisable to introduce the water from theboiler to the inlet of the low pressure s age in which event the resultswill be in line with those secured with a single stage economizer, asfar as preventing sweating and interior corrosion of the low pressurestage is concerned. Such a mode of operation is described in a companionapplication filed of even date herewith.

By returning the water from the boiler, in which the reagent may beallowed to concentrate to any desired amount, a suflicient quantity ofthe reagent may be mingled with the, water entering the economizer toprevent internal corrosion without involving undue expense, as with thesystem proposed the only addition of a reagent .is that necessary tomake up for leakage, for any water that may be blown away fromtheboilers, and for any chemical reaction which may take place within theeconomizers and boilers.

With the system proposed much more water is withdrawn from the interiorof the boiler than in usual practice where the amount of water withdrawnis only that- .which is blown off for. the removal of mud or sludge, orfor preventing over concentration, and by providing proper settlingchambers the mud or other suspended matter in the water which is drawnoii may be removed.

The invention is not, however, limited to the use of boiler water towhich a chemical reagent had been added. In its broad aspect it includesthe return of a certain amount of water from the boiler to theeconomizer. Where the water used for making up for leakage and forblowing down the boilers, or what is known as the make-up water,containsin itself the necessary elements to pre vent corrosion, noreagent need be added.'

Whether the make-up w ater'is one which requires the addition ofreagents or a water which carries the necessary elements to preventcorrosion, the present invention, prevents or lessens the tendency tocorrosion in the eco'nomizer. The following example will serve to makemy meaning clear. As- .sume that there is 10 per cent. ofemake-up watercontainingS grains of material per gallon of a nature that will tend tostop the corrosion that occurs with distilled water from the condensers.The mixture of the make-up water with the distilled water from thecondensers would contain 0.73 grains per gallon. If operated in theordinary way the water passing through the economizer would contain 0.73grains per gallon of the material that would tend to stop corrosion,whereas the water contained in the boiler might be concentrated so as tocontain say 100 grains of the same material per gallon. If now theboiler and economizer are operated in accordance with the presentinvention, and one pound ofwater containing 100 grains per gallon iswithdrawn from the boiler and mingled with 5 pounds of the watercontaining 0.73 grains per gallon, the material in the mingled waterwhich would pass through the economizer would amount to about 17 grainsper gallon, a larger amount than the original, 0.73 grains, leading toalesser amount of interior corrosion.

By practising the invention, therefore, the grains of matter tending toreduce corrosion in the numerical case considered is increased more thantwenty times over what would exist in ordinary practice.

That the concentration of certain elements in the water contained in aboiler may be much higher than in the feed water is well known in theart, and is naturally caused through the elements remaining in theboiler while the pure water is evaporated.

In the diagran'mlatic plan View of Fig. 2 I have shown my invention asapplicable to a plurality of boilers with a common mixing tank. In thisarrangement the main sup ply of water from any source, preferably fromthehot well 7, is delivered by pump 8 through a common pipe 9, havingvalved controlled branches 9, to the. low pressure stage 5 of eachboiler of the plant. After flowing through the latter the water passesby the branch connections 1Q to a common pipe 10 which conducts it tothe mixing tank 11. Leading from each boiler are valved connections 12'to a common pipe 12 by which boiler water is conducted through pipe 12to the tank 11 to be there mingled with the main supply coming from thelow presure stages of the economizers. From the tank 11 the mingledvolume is led through pipe 17 to pump 18 by which pump it is deliveredto a common pipe 19, and distributed therefrom, through pipes 19 to thehigh pressure stage 6 of each economizer of the plant. From the highpressure stage the water is conducted by a pipe 20 and valved branches20 to the corresponding boiler. The pipes 9, 10, 12 and 19 are shown asopen-ended to indicate that they may be connected to more than twoboilers, and the branch connections, 9, 10, 12 and 19 have valves forregulating the flow of waterthrough said connections or simply forclosing off the supply when a boiler is laid ofi.

Thermometers 22 are indicated as placed in the pipes 10 leading from thelow pressure stages of the economizer to the common pipe 10. Thesethermometers are important in. the operation of the plant as the valvesin the pipes 9 should be adjusted to give the desired outlet temperaturefor the low pressure stages of the economizers. If the thermometers werenot used as a guide for the adjustment of these valves, the exittemperature "for one low pressure stage might be much higher than theother.

In operating two or more boilers in ac cordance with the arrangement ofFig. 2 care must be exercised to maintain the amount of concentration inthe boilers at about the same point, for, should a matein the boilerfrom which the less amount is drawn would soon reach a higher degree ofconcentration than the other boilers. In the arrangementdiagrammatically shown in Fig. 3the necessity of making a closeadjustment of the water allowed to flow from each boiler is eliminated,as all of the water taken from the interior of a particular boiler, andmingled with the feed water, is returned to the same boiler from whichit is withdrawn.

Referring to Fig. 3, the feed water from any suitable source, such asthe hot well 7, is led through a pipe to a feed pump 23, and isdelivered through a common pipe 24 and valved branch connections 25, tothe low pressure stages 5 of the economizers. From the latter the wateris conducted through valved branch connections '26 to a common pipe 27by which it is delivered to a tank 11. From said tank the water isconducted by a pipe 28 to a feed pump 29, and is forced by the latterthrough a common pipe 30, having valved branch connections 31, intomingling tanks 32, one such tankbeing provided for each boiler. Thetanks 82 are preferably so arranged that any mud or sediment in the.

water will'settle to the bottom from whence it can be blown off throughthe valved connections 32'. Water from the boilers is led through pipes33 having valved branch connections 34 with the boilers, to pumps 35 andby the latter delivered through pipes 36 to the corresponding tanks 32.In the ordi nary operation of the plant the valves in branches 34 areleft wide open and regulating valves 37 are placed in the pipes 36between the pumps 35 and the mingling tanks 32. The water leaving thetanks 32 passes through pipes 38 into the high pressure stage 6 of thecorresponding economizer, and from the latter through pipes 39 andbranches having feed valves 40 and ordinary check valves 41, into theboilers. Thermometers 31, 42 and 43 are placed in the valved connections31 and in the pipes 36 and 38 for indicating, respectively, thetemperature oi. the feed water entering the tanks 32 the boiler waterentering the tanks 32 an the temperature of the mingled water leavingsaid tanks. By noting the difference in temperature between incoming andoutgoing water, the amount returned from the boiler to the feed watermay be determined. The pumps 35 require a comparatively small amount ofpower as they overcome only the lllfl'erence in pressure between theboiler and the feed water entering through pipe 30.

The pipes 24,, 27 and 30 are shown as open-ended to indicate that theymay-heused for more than the two boilers shown.

The mixing tank 11 is also provided with blow-off connections 11 forremoving any mud or sediment that may collect from the feed water afterit passes through the low pressure economizer stages. Where a chemicalreagent is necessary it is preferably introduced along with the make upwater, in which case the amount of concentration in each of the boilersmay be regulated by blowing ofi' more or less water from the boiler.Should a boiler be accidentally blown down to an extent that causes theconcentration of the contained water to be too low, a certain amount ofa reagent in solution may be pumped directly into the boiler by hand orby other means.

Thermometers 22 are indicated as placed in the pipes 26 leading from thelow pressure stages of the economizer t0 the common pipe 27. Thesethermometers are important in the operation of the plant as the valves26 in the pipes 26 should ordinarily be adjusted to give the desiredoutlet temperatures for the low pressure stages of the economizer.

As has been stated, the drawings are diagrammatic. Certain common andwell known features such as safety valves for the economizers have notbeen shown in order to emphasize the features which apply moreparticularly to the invention. the supply of make-up water and ofmaintaining the proper levels of water in the hot wells as well asregulating the water levels in the mixing tanks or heaters may becarried out in many well known ways. These are operating features asidefrom the principles of my invention which I have described.

By the word pressure in the claims, as applied to the mingled water inthe tank 11, I mean absolute pressure which may be either above or belowthat of the atmosphere.

What I claim and desire to secure by Letters Patent of the United Statesis 1. In the operation of boilers with artificially softened ornaturally soft water, the process which consists in passing the mainsupply of water throu h a section of an economizer, then admixlng suchwater with hot concentrated liquid from the boiler, and then forcing themingled volume to another section of the economizer at a higher pressurethan the first section of the economizer, and thence into a boiler.

2. In the operation of boilers with artificially, softened or naturallysoft water, the process which consists in passing the main supply ofwater through a section of an economizer, delivering the heated water toa tank, admixing such heated water with hot concentrated liquid from theboiler and permitting the air and gases to escape therefrom, and thenforcing the mingled volume Regulating to another section of theeconomizer at a higher pressure than the first section ofthe economizer,and thence into a boiler.

3. The herein-described method consisting in heatin the main supply ofwater in a section of an economizer, then mingling it with boiler watercontaining a chemical reagent, and then forcing the mingled volumethrough a section of the economizer subjected to the hottest gases andthence into a boiler.

4. In the operation of boilers with artificially softened or naturallysoft water, the process which consists in passing the main supply ofwater for a plurality of boilers through corresponding economizersections,

admixing the heated water from a plurality of said sections with hotconcentrated liquid from the boilers, then distributing the mingledvolume to another section of the economizers at a higher pressure thanthe first sections, and thence into the boilers.

5. In the operation of boilers with artificially softened or naturallysoft water, the process which consists in passing the main supply ofwater for a plurality of boilers through corresponding economizersections, admixing the heated water from a plurality of said sectionswith hot concentrated liquid from the boilers, then distributing themingled volume to another section of the economizers at a higherpressure than the first sections, thence into the boilers, andmaintaining a concentration of the ,Water within desired limits in thedifferent boilers.

6. In the operation of boilers with artificially softened or naturallysoft water, the process which consists in passing the main supply ofwater for a plurality of boilers through corresponding economizersections, delivering the heated water from a plurality of boilers to acommon mingling tank, ad-

mixing such heated water with hot concen-.

trated liquid from the boilers and permitting the air and ases to escape"therefrom, and then distributing the mingled volume to another sectionof the economizers at a higher pressure than the first sections, andthence into the boilers.

7. In combination, a steam boiler, a sectional economizer located in apassage for the products of combustion, connections for conducting thefeed water through said economizer, and means intermediate successivesections of said economizer permitting the escape of air from the waterand for mingling the water with a portion of the boiler water containinga chemical reagent.

8. In combination, a steam boiler, a sectional economizer located in apassage for the products of combustion, connections for conducting thefeed water at a low pressure through one section of the economizer,means intermediate successive sections for mingling the water with achemical reagent, and means for forcing the treated water under higherpressure through another section of the economizer.

9. In combination, a steam boiler, a sectional economizer located in thepassage for the products of combustion, connections for conducting'thefeed water at a low pressure through a section of the economizersubjected to the coldest gases, means intermediate si'iccessive sectionsfor mingling the feed water with a portion of the boiler watercontaining a chemical reagent, and means for forcing the water underhigher pressure through the section of the economizer subjected to thehottest gases.

10. In the operation of a boiler and economizer, the process whichcomprises establishing a relatively high concentration ofcorrosion-preventing salt in the Water in such boiler, passing the mainsupply of water through a section of an economizer, returning a portionof the liquid from the boiler and admixing the heated feedwatertherewith, and then forcing the mingled volume to another section of theeconomizer at a higher pressure than the first section of theeconomizer, and thence into a boiler.

11. In combination, a steam boiler, an economizer having low pressureand high pressure stages, a tank intermediate said stages into which thewater from the low pressure stage is passed, means for 1ntroducingboiler Water into said tank, and means for maintaining a pressure insaid tank adapted to aid in the removal of the air and gases from themingled water.

12. In combination, a steam boiler, an economizer having low pressureand high pressure stages, a tank intermediate said stages into which thewater from the low pressure stage is passed, means for introducingboiler water into said tank, and means for maintaining a pressure abovethat of the atmosphere in said tank and adapted to aid in the removal ofthe air and gases from the mingled water.

In testimony whereof I have hereunto signed my name in the presence oftwo subscribing witnesses.

]DAVID S. JACOlB US. Witnesses M. E. MoNINoH, Creams Jones.

